1. Field of the Invention
Generally, the present invention relates to an optical radiation sensor system.
2. Description of the Prior Art
Optical radiation sensors are known and find widespread use in a number of applications. One of the principal applications of optical radiation sensors is in the field of ultraviolet radiation fluid disinfection systems.
It is known that the irradiation of water with ultraviolet light will disinfect the water by inactivation of microorganisms in the water, provided the irradiance and exposure duration are above a minimum xe2x80x9cdosexe2x80x9d level (often measured in units of microwatt seconds per square centimetre). Ultraviolet water disinfection units such as those commercially available from Trojan Technologies Inc. under the tradenames UV700 and UV8000, employ this principle to disinfect water for human consumption. Generally, water to be disinfected passes through a pressurized stainless steel cylinder which is flooded with ultraviolet radiation. Large scale municipal waste water treatment equipment such as that commercially available from Trojan Technologies Inc. under the trade-names UV3000 and UV4000, employ the same principle to disinfect waste water. Generally, the practical applications of these treatment systems relates to submersion of treatment module or system in an open channel wherein the wastewater is exposed to radiation as it flows past the lamps. For further discussion of fluid disinfection systems employing ultraviolet radiation, see any one of the following:
U.S. Pat. No. 4,482,809,
U.S. Pat. No. 4,872,980,
U.S. Pat. No. 5,006,244,
U.S. Pat. No. 5,418,370,
U.S. Pat. No. 5,539,210, and
U.S. Pat. No. 5,590,390 (U.S. Pat. No. Re. 36,896).
In many applications, it is desirable to monitor the level of ultraviolet radiation present within the water under treatment. In this way, it is possible to assess, on a continuous or semi-continuous basis, the level of ultraviolet radiation, and thus the overall effectiveness and efficiency of the disinfection process. The information so-obtained may be used to control lamp output to a desired level.
It is known in the art to monitor the ultraviolet radiation level by deploying one or more sensor devices near the operating lamps in specific locations and orientations which are remote from the operating lamps. These sensor devices may be photodiodes, photoresistors or other devices that respond to the impingement of the particular radiation wavelength or range of radiation wavelengths of interest by producing a repeatable signal level (e.g., in volts or amperes) on output leads.
Conventional optical radiation sensors, by design or orientation, normally sense the output of only one lamp, typically one lamp which is adjacent to the sensor. If it is desirable to sense the radiation output of a number of lamps, it is possible to use an optical radiation sensor for each lamp. A problem with this approach is that the use of multiple sensors introduces uncertainties since there can be no assurance that the sensors are identical. Specifically, vagaries in sensor materials can lead to vagaries in the signals which are sent by the sensors leading to a potential for false information being conveyed to the user of the system.
Another problem with the prior art approach is that it is not possible to ascertain the lamp output of a single lamp in an array of lamps which operate within the field of view of a single sensor.
A further problem with prior art is that, if the U.V. transmittance of the fluid being treated was unknown, two sensors would be required to determine the dose delivered to the fluidxe2x80x94i.e., one sensor to measure lamp intensity and one sensor to measure U.V. transmittance.
Accordingly, it would be desirable to have a radiation source module comprising an optical sensor which could be used to detect and convey information about radiation from a number of radiation sources thereby obviating the need to use multiple optical radiation sensors. Further, it would be advantageous to have an optical radiation sensor device capable of detecting the lamp output of a single lamp in a lamp array.
It is an object of the present invention to provide a novel radiation source module which obviates or mitigates at least one oft he above-mentioned disadvantages of the prior art.
It is another object of the present invention to provide a novel radiation source assembly which obviates or mitigates at least one of the above-mentioned disadvantages of the prior art.
Accordingly, in one of its aspects, the present invention provides an optical radiation sensor device for detecting radiation in a radiation field, the device comprising:
a radiation collector for receiving radiation from a predefined arc around the collector within the radiation field;
motive means to move the radiation collector from a first position in which a first portion of the predefined arc is received by the radiation collector and a second position in which a second portion of the predefined arc is received by the radiation collector; and
a sensor element capable of detecting and responding to incident radiation received from the radiation collector when the radiation collector is in the first position and in the second position.
In another of its aspects, the present invention provides a radiation source module comprising a frame having a first support member; at least one radiation source assembly extending from and in engagement with a first support member, the at least one radiation source assembly comprising at least one radiation source and a radiation sensor device for detecting radiation in a radiation field, the sensor device comprising: a radiation collector for receiving radiation from a predefined arc around the collector within the radiation field; motive means to move the radiation collector from a first position in which a first portion of the predefined arc is received by the radiation collector and a second position in which a second portion of the predefined arc is received by the radiation collector; and a sensor element capable of detecting and responding to incident radiation received from the radiation collector when the radiation collector is in the first position and in the second position.
In another of its aspects, the present invention provides a method for measuring transmittance of a fluid being exposed to a radiation field having disposed therein an optical radiation sensor device, the device comprising: a radiation collector for receiving radiation from a predefined arc around the collector within the radiation field; the radiation collector being movable from a first position in which a first portion of the predefined arc is received by the radiation collector and a second position in which a second portion of the predefined arc is received by the radiation collector; and a sensor element capable of detecting and responding to incident radiation received from the radiation collector when the radiation collector is in the first position and in the second position, the method comprising the steps of:
(i) determining a first radiation intensity at the first position of the radiation collector;
(ii) producing a first output from the sensor element which correlates to the first radiation intensity;
(iii) moving the radiation collector to the second position;
(iv) determining a second radiation intensity at the second position of the radiation collector;
(v) producing a second output from the sensor element which correlates to the second radiation intensity; and
(vi) calculating the transmittance of the fluid from the first output and the second output.
Thus, the present inventors have discovered an optical radiation sensor system which allows determination of lamp output information for a single lamp in an array of lamps. An additional advantage of the present invention is that a single sensor device can be used to determine the dose delivered to the fluid (i.e., in place of the multiple sensors conventionally required as discussed above). More specifically, the present optical radiation sensor allows on-line determination of U.V. transmittance of the fluid being treated in a U.V. radiation lamp array. Yet another advantage of the present invention is that it allows for determination of reflected radiation from the walls of the reactor. Yet another advantage of the present invention it can be used to identify which radiation source in an array of radiation sources is malfunctioning or is inoperable. Other advantages will become apparent to those of skill in the art.